He was flogged 50 times on January 9 and is reportedly due to be flogged again each Friday until his sentence of 1,000 lashes has been fully carried out.

"Flogging is, in my view, at the very least, a form of cruel and inhuman punishment," said Zeid who is the U.N. High Commissioner for Human Rights said in a statement on January 15.

"Such punishment is prohibited under international human rights law, in particular the Convention against Torture, which Saudi Arabia has ratified," Zeid said.

Amnesty International reported that the blogger was made to stand with his back to onlookers as another man began flogging him, witnesses said.

Badawi did not make any sound or cry in pain. The faithful who came from noon prayers watched in silence and were ordered by security forces not to take any pictures on their mobile phones.

Reporters Without Borders said "Raef Badawi's only crime was to start a public debate on his blog about the way Saudi society is evolving, but he was sentenced for blasphemy.

"But he was given 50 lashes today before a crowd of spectators outside Jeddah's Al-Jafali Mosque and, in all, he is to receive a total of 1,000 lashes in 20 weekly sessions."

'EXTRAORDINARILY HARSH PENALTY'

Zeid appealed to the King of Saudi Arabia to exercise his power to halt the public flogging by pardoning Badawi, and to urgently review his "extraordinarily harsh penalty."

Badawi, an online blogger and activist, was convicted for peacefully exercising his right to freedom of opinion and expression.

He was sentenced to 10 years' imprisonment, 1,000 lashes and a fine of 1 million riyals (US$266,000).

Badawi's case was one of a succession of prosecutions of civil society activists.

On January 12, an appeals court upheld the conviction of Badawi's lawyer and brother-in-law Waleed Abu Al-Khair on charges that include offending the judiciary and founding an unlicensed organization. Al-Khair's sentence was extended from 10 to 15 years on appeal.

The U.N. Committee against Torture oversees the Convention against Torture and other Cruel, Inhuman or Degrading Treatment or Punishment.

The U.N. Human Rights Committee oversees the implementation of the International Covenant on Civil and Political Rights.

Both U.N. bodies have repeatedly voiced concerns about States' use of flogging and have called for its abolition.

Saudi Arabia's report on its implementation of the Convention is up for review by the Committee against Torture next year.

Saudi Arabia applies a strict interpretation of Sharia, the Islamic sharia law. It enforces the death penalty for certain offences.

Saudi authorities have repeatedly defended their penal system saying it is necessary to deter potential offenders and maintain security.

Badawi is the co-founder of the Saudi Liberal Network along with women's rights campaigner Suad al-Shammari, who was arrested in October and also accused of "insulting Islam."

"Although Saudi Arabia condemned yesterday's cowardly attack on the French satirical magazine Charlie Hebdo, it is now preparing to inflict the most barbaric punishment on a citizen who just used his freedom of expression and information," Reporters Without Borders program director Lucie Morillon said.